Study Of The Effect Of Sodium Benzoate On Body Weight And Spatial Learning And Memory Ability And Hippocampal Neuronal Morphology

PartⅠ Effect of different doses of sodium benzoate on weight and spatial learning and memory ability in ratsObjective:To observe the effect of intraperitoneal injection of different doses of sodium benzoate on weight and spatial learning and memory ability in rats.Methods:Adult male Sprague Dawley(SD) rats(160g ~ 200g) were used in the experiment,These rats were randomly divided into 3 groups: control group, sodium benzoate low-dose group(60mg / kg) and sodium benzoate high-dose group(120mg / kg), drugs were injected20 days, once a day, every other day the weight of rats were measured and recorded before intraperitoneal injection drugs. The next day after the end of injection,Morris water maze test(including place navigation test, space exploration experiments and visible platform test) were performed. Throughout the experiment consists of three parts: The main indicators escape latency of rats in place navigation test were used to evaluate the animals spatial learning ability; the number crossing the original platform of rats in space exploration experiments were applied to detecte memory ability for space of the platform position; In order to exclude the impact of movement and visual disturbances, a visible platform test was added.Results:1.The average weight of rats in sodium benzoate high-dose group was significantlylower than in the control group(P<0.05); Low-dose group of sodium benzoate did not affect weight of rats. The results show: the high-dose sodium benzoate can slow weight gain in rats.2.In place navigation test, the average escape latency of rats in three groups gradually decreased in searching for the underwater platform with the increase of training days,indicating a process of spatial learning. The escape latency of rats in sodium benzoate high-dose group was statistically significant in the navigation test,compared with the control group and odium benzoate low-dose group(P<0.05); no significant difference was noted between sodium benzoate low-dose group and control group(P>0.05).The results show:high-dose sodium benzoate will lead to lower spatial learning ability of rats.3.In space exploration experiment, although the number of crossing the original platform of rats had a general tendency of dose-dependent decrease,but no significant difference in the number acrossing target quadrant were found between groups(P> 0.05).The results show: sodium benzoate on spatial memory ability have no significant effect.4.In the visible platform trials, escape latency and swimming speed of rats were no significantly different under the conditions of the visible platform station(P> 0.05). The results show: Effect of intraperitoneal injection of sodium benzoate on spatial learning and memory does not by influencing vision and movement function.Conclusions:High-dose sodium benzoate can slow weight gain and decrease spatial learning ability in rats. The preliminary experimental results section suggest long-term use of high doses of sodium benzoate may slow down weight gain and reduce learning ability.PartⅡ Effect of different doses of sodium benzoate on hippocampal neuronal morphologyObjective:HE staining(Hematoxylin-eosin staining) and electron microscopy technology were used to observe impact of different doses of sodium benzoate on the morphology of hippocampal neurons.Methods:The next day of the end of behavioral experiments, brain tissue of rats was removed after being anesthetized, HE staining and electron microscopy technology were used to observe the structure of hippocampal neurons.Results:1.In HE staining experiment, hippocampal CA1 region neurons of rats in sodium benzoate low-dose groups were sparse,showing disorder and arrangement; In sodium benzoate high-dose group, the hippocampal neurons in CA1 region showed up as disorder,irregular, cell gap increases, some cytoplasmic edema, nuclear pyknosis,In DG region neurons cell are disorder, nuclear pyknosis, cytoplasmic concentration compared with that in control group. The results show:small dose of sodium benzoate can damage hippocampal CA1 region neurons,and in high-dose sodium benzoate group hippocampal neuronal morphology in CA1 and DG region are damaged obviously.2. In Electron microscope experment, hippocampal neurons of rats in control group showed up as structural integrity of cell membranes, organelles rich, complete mitochondrial structure, normal myelin sheath structure; The hippocampal neurons of rats in sodium benzoate low-dose group had not changed compared with the control group; The hippocampal neurons were membrane vague,showing fewer organelles, the mitochondria edema or barren damaged and myelin damage lax in sodium benzoate high-dose group.The results show: The hippocampal neuronal morphology of ultrastructure of cell,organelles, myelin are damaged in sodium benzoate high-dose group of rats.Conclusions:The high-dose sodium benzoate can damage the hippocampus neurons. Initial prompt sodium benzoate on hippocampal neurons damage does exist.In short, In this study, introducing the same group of animal models, and a variety of techniques( Morris water maze and HE staining) were used to prove the toxic effects on spatial learning and memory of sodium benzoate, and to explore the morphological basis for this action might be involved. To further study the basic sodium benzoate provided experimental evidence on learning and memory.